Controversial legislation establishing marriage and adoption rights for same-sex couples cleared final passage in France on April 23 after a 331-to-225 vote in the left-controlled Parliament. But the protests it has prompted in recent months aren’t likely to fade any time soon. As France’s opposition conservatives promise to mount legal challenges to block the law’s application, leaders of the well-organized and vocal groups who’ve fought the measure will continue denouncing it as an attack on matrimony and the traditional family unit.

The French lower house of Parliament on Tuesday passed the so-called Marriage for All bill, which opens marriage and adoption to same-sex couples with identical rights previously limited to heterosexual unions. That vote — which was largely split down left-right lines — makes France the ninth E.U. member and the 14th nation in the world to legalize same-sex marriage. Opponents decried the legislation — which was one of Socialist President François Hollande’s main campaign promises — as deforming time-honored definitions of marriage and endangering children by permitting gay and lesbian couples to adopt. French public opinion was mixed: polls have consistently shown around 60% of people favoring legalization of same-sex marriage, with a small majority opposed to adoption rights accompanying that reform.

Indeed, given France’s rather liberal, live-and-let-live social reputation abroad, it struck some foreign observers as ironic the French took so long — and battled so bitterly — to legalize same-sex marriage that purportedly stodgier “Anglo-Saxon” countries like the U.S. and U.K. now appear to be moving toward rapidly. Be that as it may, backers of Marriage for All cheered its final passage — and expect, once the law clears constitutional review in late May, the first legal same-sex marriages to be performed in June.

“It’s a generous law, and a law of equality,” an elated Christiane Taubira, Socialist Justice Minister and author of the bill, told Parliament after the vote. “We believe the first weddings will be beautiful and that they’ll bring a breeze of joy, and that those who are opposed to them today will surely be confounded when they are overcome with the happiness of the newlyweds and the families.”

That’s a nice thought, but the deep divisions that have erupted and spread across France since Marriage for All was introduced in November will not close quickly — as opponents now warn. Political conservatives, social traditionalists and members of all of France’s main religious organizations have loudly voiced their common hostility to a measure they see as deforming the institution of marriage and family unit. Banding together in collective protests, opponents of the legislation staged numerous demonstrations in cities across France and drew as many as 800,000 people during one of four Paris marches. Leaders warn they’ll neither dissolve the movement, nor ease pressure on political leaders until the pending law is rescinded.

The size and militancy of the gay-marriage opposition appear to have increased with time. That also includes indications that extremist elements from the French far right may have also joined the movement. Overtly homophobic slogans were carried and chanted by small clusters of demonstrators in recent Paris marches, where clashes with police also occurred.

Similar violence has also broken out between cops and demonstrators who gathered each night outside Parliament ahead of the April 23 vote. That’s not the only way the protest movement — or people claiming to be part of it — has radicalized. Savage attacks on gay men have also recently occurred in Paris, Lille, Bordeaux and Nice amid what backers of Marriage for All claim is an intolerable atmosphere of homophobia created by the proposal’s enemies.

Leaders of the protest movement have denied any homophobic sentiment or intent behind their campaign, and they have denounced the recent insults and attacks on gays and lesbians across France. They’ve been less apologetic, however, about the ways gay-marriage opponents have targeted politicians and pundits who’ve led the push for the reform’s swift passage into law.

Struggle over Marriage for All has challenged politics-as-usual in other ways as well. Though virtually all leftist legislators fell in behind Hollande’s landmark social reform throughout its voyage to Tuesday’s vote, the measure split the centrist Union of Democrats and Independents party into starkly opposing camps of people supporting or rejecting the bill. Meantime, several members of the conservative Union for a Popular Movement (UMP) party wound up abstaining while fellow members voted against the text. Most of those UMP holdouts — many younger party risers who served in cabinets of by ex-President Nicolas Sarkozy — had previously expressed their personal support of a reform, even if politics prevented them from voting for it. Six UMP legislators bucked the party’s line and cast votes backing the bill.

But common opposition to Marriage for All inspired several UMP officials to march alongside legislators from the extreme-right National Front (FN) during an April 21 protest in Paris. That broke a long-standing taboo among mainstream conservatives prohibiting association or partnership with the toxic far right — a precedent some political analysts think may eventually see a block of the UMP breaking off to occupy far-right positions traditionally monopolized by the FN. Such expectations suggest that if Marriage for All creates the legal opportunity for wedded bliss for same-sex couples, it’s only just started provoking serious domestic unrest within some of France’s political families.